Two-way cushion for contactor



March 29, 1966 E. T. PLATZ E TAL Two-WAY CUSHION FOR CONTACTOR Filed May24, 1963 5 Sheets-Sheet 1 K x m? mm m a: e 4

March 29, 1966 PLATZ ETAL 3,243,545

TWO-WAY CUSHION FOR CONTACTOR Filed May 24, 1963 5 Sheets-Sheet 2 Mardl6 E. T. PLATZ ETAL 3,243,545

TWO-WAY CUSHION FOR CONTACTOR Filed May 24, 1963 5 Sheets-Sheet 5 UnitedStates Patent 3,243,545 TWO-WAY CUSHION FOR CONTACTOR Elwood T. Platz,Grosse Pointe Farms, and Andrew J.

Kralik, Detroit, Mich., assignors to I-T-E Circuit Breaker Company,Philadelphia, Pa., a corporation of Pennsylvania Filed May 24, 1963,Ser. No. 283,084

9 Claims. (Cl. 20087) This invention relates to contactors in generaland more particularly to an improved means for absorbing shocks whichare generated when the contactor magnet is energized.

In the Cataldo et al. copending application Serial No. 189,915, filedApril 24, 1962, entitled Electrical Device," and assigned to theassignee of the instant invention, there is disclosed a contactor of thetype to which the instant invention is applicable. Briefly, thecontactor is a multiphase unit having two stationary contacts and amovable bridging contact for each phase. The bridging contacts of allphases are operatively connected to the armature of an electromagnet.The magnet yoke is positioned by 'a cushion mounting so that the shockswhich are generated upon the engagement of the armature with the magnetwill minimize damage.

It is not only the direct impact of the armature engag ing the yokewhich must be absorbed but there is also a rebound shock which must beabsorbed. Some prior art constructions attempt to absorb both the directand rebound shocks by utilizing a single spring member. This has provento be less than satisfactory since the shock absorbing means must betied to the same means which positions the yoke relative to the armaturefor the deenergized condition of the electromagnet. It is essential thatthe air gap between the two magnetic core members be accuratelycontrolled and that this gap not vary appreciably when the contactor issubjected to external shock forces. By utilizing a single shockabsorbing memher in an efiort to accomplish both direct and reboundshock absorption it is necessary to resort to compromises and as aresult it is necessary to settle for less than top a performance.

The instant invention overcomes this difficulty of the prior art byproviding a construction in which one spring means is utilized for theabsorption of direct shocks while another spring means is utilized forthe absorption of rebound shocks. The construction is such that uponrebound contact separation or lift-off is substantially prevented sothat arcing, hence contact erosion, is minimized. Further, the magnetyoke is not rigidly tied to the stationary base so that the former isnot tied to a large encumbering mass. The yoke is relatively free torecoil under the shock of closing thereby reducing distortion and wearat the pole faces.

In some of the embodiments to be hereinafter described, means are alsoprovided for adjusting the yoke relative to the armature so that air gaplength may be accurately controlled. Not only are the shock absorbingabilities of the device of the instant invention vastly superior tothose of similar prior art devices, but in addition the shock absorbingmeans is so constructed that assembly of the contactor is facilitated.

Accordingly, a primary object of this invention is to provide a novelshock absorbing means for an electromagnetic contactor.

Another object is to provide a shock absorbing means of this type havinga novel construction in which a means is provided for the absorption ofdirect shocks and a separate means is provided for the absorption ofrebound shocks.

Still another object is to provide a novel means for mounting the magnetyoke of a contactor such that the 3,243,545 Patented Mar. 29, 1966adverse effects of armature impact on contact life and pole faceconformation will be minimized.

A further object is to provide a cushioning means of this type havingmeans for adjusting air gap length between the armature and yoke for thedeenergized condition of the electromag'net.

These as well as further objects of this invention shall become readilyapparent after reading the following description of the accompanyingdrwings in which:

FIGURE 1 is an exploded perspective of the main elements of a contactorincorporating the novel shock absorbing means constituting the instantinvention.

FIGURE 2 is a load side view of the contactor base with the magnet yokeand retaining elements mounted thereto.

FIGURE 3 is a plan view of the contactor base with the magnet yoke andretaining elements mounted thereto.

FIGURE 4 is an exploded perspective of the magnet yoke and the shockabsorbing elements.

FIGURE 5 is a fragmentary view partially sectioned t0 illustratedanother embodiment of the invention in which two elements are providedfor adjusting the air gap length between the leg and armature for thedeenergized condition of the electromagnet.

FIGURE 6 is a view similar to FIGURE 5 illustrating a third embodimentof the instant invention.

Now referring more particularly to FIGURES 1 through 4. Contactor 10 isa multiphase unit 'of the type described in detail in the aforesaidcopending application 189,915. Each phase is provided with a bridgingelement 11 which is movable downward with respect to FIGURE 1 intoengagement with a pair of stationary contacts 12a, 12b. All of thestationary contacts 12a, 12b are secured to plate 13 which is mounted infixed position upon molded insulating base 14 with the latter beingsecured to mounting plate 15. It is noted that in operation plate 15 ispositioned in a vertical plane so that all of the elements of thecontactor are deemed to be mounted on the forward side of plate 15.

Each of the bridging contacts 11 is mounted at the forward end of aprojection 16 extending forwardly from movable contact carrier 17. Thelatter is mounted to the rear of plate 13 being biased thereagainst bytwo coil springs 18, only one of which is shown in FIGURE 1. Studs 19extend through coil springs 18 and clearance apertures in contactcarrier 17, into plate 13, so as to constitute guides for the movementof carrier 17 relative to plate 18. Springs 18 are coiled compressionelements with one end of each resting against the rear surface ofcarrier 17 and the other end resting against the enlarged head of stud19. Plate 13 carries pivotally mounted clips 21 which removably securecover 22 in operative position to cooperate with plate 13 in coveringthe contacts 11, 12a and 12b of all phases.

Secured to contact carrier 17, in a manner described in detail in theaforesaid copending application 189,915 is U-shaped armature -25 whoselegs extend rearwardly. When the plate-contact carrier assembly 30 ismounted to base 14, the heads of studs 19 rest against fixed portions ofbase 14 so that plate 13 is fixed in relation to base 14. Screws securestationary contacts 12a to line terminals 29 and other screws securecontacts 12b to load terminals 28.

Coil springs 18 position pole faces 25a and 25b a sembly 40 is providedwith two contact buttons 39 which .engage spring contacts 38 mounted inbase 14. It is noted that portions of the enlarged heads of studs 19rest against the forward surface of coil assembly 40 to limit forwardmovement thereof.

Serpentine leaf spring 44 is interposed between base 14 and the rearsurface of the yoke web 350, being disposed within base pocket 45 whichreceives the yoke web 35c. Yoke'35 is secured to base 14 by means of twosets of elements. Each of these sets comprise a plate 46 a coil spring47, and a retainer 48.

Edge 46a of plate 46 extends into side recess 35d of yoke 35. It isnoted that the height of recess 35d is considerably greater than thethickness of plate 46 so that a lost motion connection is formed betweenyoke 35 and plates 46. The arms 48a, 48b of U-shaped retainer 48 receivebase formation 14a therebetween. Coil spring 47, disposed within recess14b of base formation 14a, is a compression member one end of whichbears against the forward boundary of recess 14b and the other end ofwhich extends beyond the rear end of recess 14b and bears againstretainer arm 48b.

Plate 46 is interposed between retainer arm 48a and surface 14c of baseformation 14a. Retainer 48 is resiliently held in place by virtue of thefact that the outwardly extending wing tip of retainer arm- 48a arepositioned inwardly of plate ears 46b.

As seen in FIGURE 2, when magnet coil assembly 40 'is deenergizedserpentine spring 44 urges yoke 35 forwardly so that the rear boundaryof yoke slot 35d engages plate edge 46a to establish the desiredposition for yoke 35 relative to base 14.

When coil assembly 40 is energized, the direct impact of armature 25engaging yoke 35, yoke 35 moves to the rear and the shock is absorbed byserpentine spring 44. However, during this period certain rebound forcesare generated due to the fact that spring 44 is being deformed, openingsprings 18 are being compressed and the contact pressure springs (notshown) are also being compressed. Thus, a rebound force of considerablemagnitude is built After the direct closing the shock is absorbed byserpentine spring 44, yoke 35, armature 25 and contact carrier 17rebound as a unit. If plates 46 were not resiliently mounted the reboundshock would cause excessive damage. However, as yoke 35 moves forwardthe inward edge 46a of plate 46 also moves forward. This movement ispermitted since retainer leg 48b rests against the rear end of spring 47and is free to move at least as far as the surface 14d of base formation14a. Prior to engagement the rebound forces have been expended.

Springs 47 are so constructed that their combined forces is slightly inexcess of the normal steady combined forces of return springs 18,contact pressure springs (not shown) and thespring of any interlockdevice which may be connected to contactor 10.

In the embodiment of FIGURE the same serpentine spring 44 is utilized toabsorb direct shocks. Plate 60 which extends into yoke recess 35 ismaintained against base surface 61 by conical coiled compression spring62 with the wide end of spring 62 hearing against plate 60 and thenarrow end of spring 62 bearing against the head of retaining screw 63.Screw 63 extends through spring 62 and the base formation which includessurface 61 with the end of screw 63 remote from its head being engagedbynut 64 whose position determines the loading of spring 62. Nuts 65aand 66a are mounted within recesses of base 67 adjacent to surface 61with these recesses being shaped so that nuts 65a, 66a are preventedfrom rotating. Threadably mounted to nuts 65a and 66a are adjustingscrews 65 and 66, respectively.

Yoke 35 is moved forwardly by turning screw 66 so that it moves towardplate 60. Similarly, yoke 35 is moved rearwardly by turning screw 65 sothat it moves forward. After all of the adjustments have been made, a,suitable sealer may be applied to assure thatthese adjustments willremain fixed.

In the embodiment of FIGURE 6 compression coil spring 71 disposed withina base recess engages the outer end 72a of plate 72 urging plate 72forward into engagement with bracket 73 secured to the base by screwretainer 74. The inner end 725 of plate 72 extends into yoke recess 35d.The engagement of yoke 35 with plate 72 in its normal position of FIGURE6 establishes the normal position for yoke 35 relative to the base.Adjustment of screw 74 determines the position of bracket 73, hence theposition of plate 72.

As in the other embodiments serpentine spring 44 provides a cushion fordirect shock. During rebound yoke 35 attempts to move forward. Thiscauses the innerend 72b of plate 72 to move forward so that plate 72pivots about bracket 73 at edge 73a with the outer end 72a of bracket 72compressing spring 71.

Thus, this invention provides a novel construction for a shock absorbingmeans utilized with contactor magnets. The construction is such thatindividual spring elements are utilized for absorbing direct and reboundshock forces so that no compromises need be made. This results inminimizing the adverse effects of armature impact on con tact life andpole face conformation.

Although there has been described a preferred embodiment of this novelinvention, many variations and modifications will now be apparent tothose skilled in the art. Therefore, this invention is to be limited,not by the specific disclosure herein, but only by the appending 0 arms.

The embodiments of the invention in which an excluisive privilege orproperty is claimed are defined as folows:

1. A device for the class described comprising a set of cooperatingcontacts and an electromagnet operatively connected to said contacts foroperation thereof; said electromagnet comprising a core and anenergizing winding therefore; said core comprising a movable core memberand a relatively stationary core member; means biasing said first coremember away from said second core member; means mounting said first coremember for movement in a first direction toward said second core memberupon energization of said winding; first means supporting said secondcore member and constituting means for absorbing direct shock broughtabout by engagement of said second core member; second means .separatefrom said first means for normally limiting movement of said second coremember in a second directron toward said first core member; said secondmeans including a resilient portion operatively engaging said I secondcore member so as to yield to a limited extent as said second coremember rebounds under the influence of said first means, said secondmeans includes a plate, a spring, and a stop; said spring urging saidplate against said stop; said plate extending into a recess in saidsecond core member; said recess and said plate being so proportioned asto permit movement of said second core member relative to said stop.

2. The device of claim 1 in which the first means normally urges aportion defining said recess into engagement with said plate, said firstmeans constructed to permit said portion to disengage said plate uponthe occurrence of direct shocks.

3. The device of claim 2 in which said portion engages said plate assaid second core member rebounds thereby causing said plate to moverelative to said stop.

4. The device of claim 3 in which the second means also includes aU-shaped retainer having a first and a second leg; said spring engagingsaid first leg and urging said retainer in said first direction; saidsecond leg being in engagement with said plate with said plate beinginterposed between said stop and said second leg.

5. The device of claim 2 in which the spring directly engages saidplate; said stop being comprised of adjustable means whereby theposition of the second core member relative to the first core member isadjustable to a desired position when said winding is deenergized.

6. The device of claim 5 in which said stop is comprised of screw meansdirectly engaging said plate.

7. The device of claim 2 in which one end of the plate extends into therecess of the second core member and the spring directly engages theplate near the other end thereof.

8. The device of claim 7 in which stop includes an edge defining a pivotabout which said plate is rockable during the process of absorbingrebound shocks.

9. The device of claim 8 in which the stop is adjustably mounted wherebythe position of the second core 61, member relative to the first coremember is adjustable to a desired position when said winding isdeenergized.

References Cited by the Examiner UNITED STATES PATENTS 584,050 1/ 1947Great Britain.

BERNARD A. GILHEANY, Primary Examiner.

ROBERT K. SCHAEFER, Examiner.

B. DOBECK, Assistant Examiner.

1. A DEVICE FOR THE CLASS DESCRIBED COMPRISING A SET OF COOPERATINGCONTACTS AND AN ELECTROMAGNET OPERATIVELY CONNECTED TO SAID CONTACTS FOROPERATION THEREOF; SAID ELECTROMAGNET COMPRISING A CORE AND ANENERGIZING WINDING THEREFORE; SAID CORE COMPRISING A MOVABLE CORE MEMBERAND A RELATIVELY STATIONARY CORE MEMBER; MEANS BIASING SAID FIRST COREMEMBER AWAY FROM SAID SECOND CORE MEMBER; MEANS MOUNTING SAID FIRST COREMEMBER FOR MOVEMENT IN A FIRST DIRECTION TOWARD SAID SECOND CORE MEMBERUPON ENERGIZATION OF SAID WINDING; FIRST MEANS SUPPORTING SAID SECONDCORE MEMBER AND CONSTITUTING MEANS FOR ABSORBING DIRECT SHOCK BROUGHTABOUT BY ENGAGEMENT OF SAID SECOND CORE MEMBER; SECOND MEANS SEPARATEFROM SAID FIRST MEANS FOR NORMALLY LIMITING MOVEMENT OF SAID SECOND COREMEMBER IN A SECOND DIRECTION TOWARD SAID FIRST CORE MEMBER; SAID SECONDMEANS INCLUDING A RESILIENT PORTION OPERATIVELY ENGAGING SAID SECONDCORE MEMBER SO AS TO YIELD TO A LIMITED EXTENT AS SAID SECOND COREMEMBER REBOUNDS UNDER THE INFLUENCE OF SAID FIRST MEANS, SAID SECONDMEANS INCLUDES A PLATE, A SPRING, AND A STOP; SAID SPRING URGING SAIDPLATE AGAINST SAID STOP; SAID PLATE EXTENDING INTO A RECESS IN SAIDSECOND CORE MEMBER; SAID RECESS AND SAID PLATE BEING SO PROPORTIONED ASTO PERMIT MOVEMENT OF SAID SECOND CORE MEMBER RELATIVE TO SAID STOP.